The present invention relates to an information processing system having an operation console operated by an operation processor, and more particularly to an information processing system provided with a fault diagnostic unit using a novel operation processor including a microprocessor and an information processing unit including an improved hardware system which is suitable for performing fault diagnosis.
By convention, an operation console has been used mainly for communication between an operating system and an operator. In general, the hardware of the console has been designed aiming at provision of smooth and effective communication between the operating system and the operator. Many attempts have been made to reduce the cost of the total system. One of them is to properly share the work between the operating system and the operator in accordance with the character of the work. Another is to assign the functions of fault diagnosis of the system, the loading of firmware, and the like. The result of this is a versatile application of the operation console.
However, when the hardware of the CPU malfunctions, proper operation of the operating system per se is impossible and the operation console merely displays its fault condition. Accordingly, all the processing must be done by an operator. For this, a manual for operators is prepared describing how to judge the abnormal states and how to cope with them for various possible cases of faults. Accordingly, the operators must be skilled in the manual. Further, a maintenance panel is used for displaying the inner state of the faulty CPU.
Therefore, disadvantages of the conventional operation console are as follows: `(1) Since fault conditions rarely occur, it is very difficult for the operators to master the manual contents. If they know it only roughly, they are insufficient for smoothly dealing with abnormal conditions.
(2) The hardware for indicating the internal status of the CPU is expensive. Particularly, the data path for the fault indication may be cheaply manufactured; however, the assembling and wiring cost of the panel is expensive.
(3) The maintenance panel is assembled from a large number of switches and lamps. This results in poor operation.
The information processing unit generally has a main memory unit storing a number of instructions and successively executes the instructions for effecting its purpose. The unit additionally includes various kinds of hardware for fault diagnosis, maintenance work, firmware loading, fault detection, and the like. In the following specification, these hardware systems will be referred collectively to as maintenance/diagnostic hardware. An effort has been made to make maximum use of common hardware items. However, the use, object, and control master (operators, maintenance engineers, diagnostic programs) are different so that such an effort has been unsuccessful. Therefore, the number of hardware items in use is large and they are generally complex and difficult to understand.